1. (2019一下·尖草坪期末) 口算

63-7=          48-3=          12-7=          5+43=         17-8=

56-8=          11-8=          4+45=          14-7=         66-5=

16-9=          49+3=         25+20=         12-8=          17+60=

92-40=         72-60=         7+40=         60+3=          5+27=